Production of High Surface Area Activated Carbon from Peanut Shell by Chemical Activation with Zinc Chloride: Optimisation and Characterization

Abstract

The potential of peanut shell as a precursor to produce activated carbon by chemical activation with ZnCl2, and the effect of activation variables were investigated using response surface methodology. Activation variables examined were temperature, hold time and impregnation ratio; among these, impregnation ratio and temperature were found to most affect the final characteristics of the produced activated carbon. The activation process was mapped, using design of experiments, and the optimum activation conditions were found to be a temperature of 485 °C, with a hold time of 15 min and an impregnation ratio of 1.7. Under the optimised conditions, an activated carbon with a relatively high surface area of ~ 1700 m2/g was produced, at a yield of 47%. Moreover, the carbon exhibited a relatively high density, ranging from 1.455 g/cm3 to 1.750 g/cm3, as well as a low ash content below 1% and a high fixed carbon content above 86%. SEM analysis and FTIR characterisation revealed the heterogenous nature of the produced carbon materials. The developed materials, with potential as adsorbents, removed up to 99.8% of a target dye (methyl orange) depending on their available surface area. Hence, through the insights gained, an optimised carbon is produced, demonstrating the potential to tailor activated carbon materials produced from waste biomass.